Means for sharpening bits



Oct 6, 1942- w. J. MOERLIN TAL 2,298,018

MEANS FOR SHARPENING BITSl Filed July l0, 1939 Patented Oct. 6, 1942 y 2,298,01c 'sir orgies MEANS FOR SHARPENING BITS William J. YMoerlin and Robert C. Berggren, Denver, Colo., assignors to The Mine and Smelter Supply Company, Denver, Colo., acorporation of'Colorado Application July I0, 1939, SerialNo. 283,579v

(Cl. 90A-11) 6 Claims.

This invention relates to improved Imethodand means for maintaining detachable rock drill bits or the like in optimum operating condition.

As is very well known to those skilled in the art, detachable rock drill bits are being quite extensively used in the mining industry and in other industrieswhere rock drilling is practiced. When the drill bits are used, they are removably attached to an operating shank or rod, usually by a threaded socket in the bit being engaged by a similarly threaded end on the shank or rod.

Such bits ordinarily have a plurality of radial' cutting edges, and as they are used, these edges become dull and require sharpening. Such detachable bits are usually of a general frusto-conical shape, the cutting edges .being positioned radially at the large end and the socketed connection at the smaller end. If these cutting edges are sharpened by removing rnetal therefrom, as is the common practice, the bit tends to lose its original cutting dia-meter or gage, which is objectionable. Therefore, it is highly desirable to maintain cutting diameter or gage on such a bit.

An excellent way to sharpen detachable rock bits of this character is to heat them red hot and mill them with a specially designed milling cutter while they are in this heated condition. Handling such heated bits for so sharpening them, presents certain difficulties.

Therefore, it is an object of the present inventionv to provide an improved method rand means for sharpening detachable rock drill bits and maintaining their cutting diameter or gage.

Another object is to provide such a method and means that may be used quickly and conveniently by anoperator to so recondition such a bit.

A further object is to yprovide an improved method and means for handling and reconditioning heated detachable rock drill bits or the like, that may be kept in constant operation without overheating said means.

Still another object is to provide in such a -method and apparatus, means for moving a hot detachable bit or the like, from a sharpening position to a gage-cutting position in one prompt, continuous operation.

yA still further object is to provide means for rotating a hot bit adjacent a gage-cutter.

Other objects and advantages reside in details of design and construction which will be more fully disclosed in the following description and in the drawing wherein like parts have been similarly designated and in which:

linY order to illustratek a practical reduction to practice of this inventive concept, inclusive of typical means for performingthe improved method, the accompanyingdrawing is presented herewithand will. be described in detail. No limitation of this invention is intended to be expressed or implied by this example given. The scope of the inventive concept is to be measured Iby the appended claims.

In the drawing,y reference character 5 denotes a hollow built-up metallic base, upon which is mounted a motor 6 having a V-faced milling cutter 'I which preferably is rotated in a clockwise direction as viewed in Figure 1.

Another motor B is mounted upon the ibase 5 and spaced away from the motor 6. The second motor 8 .has .a milling cutter 9 that is adapted to gage-cut the exterior surface of a detachable drill bit or the like, that is positioned and held adjacent thereto.

'Ille :base 5 has a lateral projection 5a, upon which is rotatably journalled a mechanism for holdingv and presenting detachable -rock bits or the like, tothe milling cutter 'I and then to the gage-cutter 9 in a. brief, continuous operation while said4 bit ishot.

The mechanism for holding and presenting hot detachable Ibits to the. milling cutter for sharpeningv and then to the gage-cutter, preferably is built up as follows:

A spindle I0 is slidably mounted in a water jacketed sleeve I2 having means I3 for circulating water therethrough, from any convenient source not shown. A bit holder I4 is rotatably positioned through the spindle I0 and is shaped at one endV to. receive the socket of a detachable rock drillbit or the like, designated at I5. The opposite end of the holder I4 is provided with an. indexing star I6 which is positioned and `adapted to contact a pawl II mounted on the base 5., when the bit holder isY moved, as will be more fully set forth.

' The spindle I0, together with the water jacketed sleeve I2 and the bit holder I4, are carried upon an arm I8 which in turn is attached to a hollow shaft I9 journalled in bea-rings 2D for limited rotary movement by means of a handle 2l affixed thereto.

Extendingl through the hollow shaft i9 is a solid shaft 22` that is rotatable with reference to said hollow shaft I9 by means cf aratchet assembly 235 selectively. operable by a handle 2li. The ratchetassembly 23-24 is adapted to rotate the solid shaft. 22 in stages of a relatively few degrees to any one of a number of predetermined positions. At the end of shaft 22v that is opposite the ratchet 23, an eccentric 25 is affixed thereto. A connecting link 2'5 pivotally joins the spindle IB, by means of a lug Ia thereon, to the eccentric 25 so that Vby angular or rotary movement of the shaft 22, the spindle I is caused to move longitudinally in predetermined increments.

When the hollow shaft I9 is rotated toward the milling cutter 1, the detachable bit I positionedv on the bit holder I4 may be presented to said milling cutter for removing metal therefrom to sharpen the cutting edges thereof. Bosses 21 on the sleeve I2 are positioned and adapted to contact a pair of stops 28 positioned on the base element 5 to thereby limit the angular movement of the mechanism toward milling cutter 1. Rotation of the shaft 22 will longitudinally advance or retract the spindle I9 and the bit holder I 4, with the result that the detachable bit I5 may be presented properly to the milling cutter 1.

If the milling cutter 1 runs clockwise, as viewed in Figure 1, i. e., from the center toward the outside edge of the bit I5, in the position illustrated, the hot metal of the bit will tend to be dragged or upset outwardly as the cutting edges thereof are sharpened. This action tends to maintain the gage of the bit, which otherwise would tend to be lost, as hereinabove explained.

However, the bit I5 may be presented to the milling cutter 1 adjacent the lower part of the periphery thereof, in which position the milling action will be reversed with reference to the bit, in that the milling cutter will move toward the center of the bit. This will effect an equally satisfactory sharpening of the bit although the outward upsetting tendency will be lacking.

Usually, there are four radial chisel-like cutting edges on each detachable bit. Therefore, to sharpen a bit such as shown at I5, the said bit must be presented to the sharpening cutter 1 in four positions so that said cutter may operate in each V-shaped space between the cutting edges. To rotate the hot bit I5 so as to present it in four positions to the milling cutter 1, the bit holding assembly as hereinabove set forth, is moved away from the milling cutter 1, by means of the handle 2|, sufficiently to bring the indexing star IB in contact with the pawl I1 thereby to rotate the bit holder I4 and the bit I5 about 90. 'Ihis indexing operation is repeateduntil all of the cutting edges of the bit have been properly milled to sharp edges.

After the cutting edges of the bit I5 have been sharpened as above set forth, the next operation is to gage-cut the bit. 'Ihe method and apparatus for positioning and gage-cutting the hot bit in the same continuous operation, will next be set forth. An arm 29 is journalled for free arcuate movement upon the hollow shaft I9 adjacent one of the bearings 2|).V If desired, a. counterweight 30 may be a'xed to the arm 291 to counterbalance the weight of said arm and thereby to reduce the amount of force required to move it about its axis of limited rotation.

As illustrated in Figure l, the angularly movable arm 29 is held in a predetermined position by means of 'a stationary cam 3| on one of the bearings 20, engaging a follower 32 carriedl upon a slide 33 that is. urged toward the cam by means of a spring 34 bearing against a bracket 35 affixed to the arm 29 and bearing against a collar 36 axed to a rod 31 attached to the slide 33 and guided by means of said bracket 35 andl i another similar bracket 38 `also attached to the arm 29.

The slide 33 and its associated mechanism are movable along and with reference to the arm 29. The slide 33 carries a hand Wheel 39 which is adapted to rotate a bit-driving head 4U through the intermediary of suitable gearing, shown in dotted lines at 4|.

When the bit holder assembly is moved away from the milling cutter 1 by means of the handle 2| toward the arm 29, the sleeve I2 comes in contact with a contact member 42 afxed to the arm 29, whereupon said arm 29 and its associated mechanism begin to move angularly and conjointly with the bit holder assembly. The

force for such further angular movement is supplied manually through the intermediary of the handle 2| and is suicient to force the camfollower 32 out of its retaining notch in the cam 3|, and as the entire assembly continues to move arcuately, downwardly and to the right as viewed in Figure 1, the cam-follower 32 will permit the slide 33 and, therefore, the bit driver 40 to slide or move inwardly toward the bit I5 so that said driving head 40 will engage the points or cutting edges or the grooves therebetween, of the bit I5 as clearly illustrated in Figure 2. As a part of contact member 42, a more positive latch between the arm 29 and the bit holder assembly may be provided and controlled by movements of the cam follower 32. If desired, an operator may begin turning hand wheel 39 to rotate driving head 49 to facilitate the engagement of said driving head 40 with the bit I5 as they conjointly move downwardly about their general and common pivotal axis.

A stop member 43 is positioned upon the base 5 to stop the downward arcuate movement of the arm 29 in a position to present the detachable bit I5 to the gage-cutter 9 which is driven by the motor 8. Rotation of the hand wheel 39 will drive or turn the bit I5 to present all sides thereof to the gage-cutter 9.

After the gage-cutting has been completed, the handle 2| is rotated counter-clockwise as shown in the illustrations, to restore the arm 29 and its associated mechanism to the position illustrated in Figure l where it is automatically held until the next bit is to be sharpened. The upper movement of the arm 29 and its associated mechanism causes the slide 33 to move -away from the bit I5 as the follower 32 moves along the cam I3, thus to release the engagement of the driving head 40 from the bit I5.

If a further latching engagement is provided between the arm 29 and the bit-holding assembly, then such engagement would also be released by movement of the cam follower 32, whereupon the bit I5 having been sharpened and cut to gage, may be removed. As above stated, the sharpening milling cutter 1 may be rotated in either direction, but it is usually preferable to turn this milling cutter from the center toward the outer edge of the bit to upset the hot metal of the bit outwardly and thus maintain its cutting diameter or gage.

As clearly illustrated in Figure 1, it appears preferable to provide raised portions 5b and 5c on the hollow base 5, upon which to mount the motors 6 and 8. This arrangement provides a lower -central area on the base 5, above which the bit holding mechanism operates. Immediately below the milling cutter 1 is a duct 44 and im- ;mediately below the milling cutter 9 is another duct 45. These ducts are open at their tops and connected with the hollow interior of the base 5 so that cuttings and fumes from the bits being sharpened will be drawn downwardly therethrough into the hollow base 5.

An exhaust fan 46 that may be driven by any suitable means, such as an electric motor not shown, is connected at 41 with the hollow interior of the base adjacent the bottom thereof. Fumes are thus drawn from the interior of the base and away from the operator. The hot chips or cuttings from the bits are thrown downwardly into pans 48. The cuttings are directed into the pans by means of a plurality of inclined baiiies 49, which feature is of importance because the hot chips from the bits tend to form a hard slag, and unless they definitely are directed into the pans 48, they would tend to cake upon the bottom of the base 5 and might cement the pans 48 thereto. The pans 48 normally are removable from the base, access thereto being had through doors 50.

In order to position the motor 8 which drives the gage-cutting miller 9, in proper relationship to the bit l5 for cutting it to gage, a plurality of adjustments are provided for said motor. A plate 5I is movable transversely of the axis of the bit I5 along rails 52 by means of a hand wheel 53 operating a thrust screw 54. Another plate 55 is superposed upon the plate 5I and is movable parallel to the axis of the bit l5 by means of a hand Wheel 56. Another plate 51 is mounted upon the plate 55 and is angularly movable to adjust the angle of the gage-cutting miller 9 with reference to the bit I5 by means of a hand wheel 58. The motor 8 is carried upon the plate 51 and therefore is subject to all of the above enumerated adjustments.

Briey, the present method consists in supporting a red hot bit, presenting it to a sharpening milling cutter While so heated, thus subjecting it to a combined upsetting and sharpening action, automatically rotating the bit to present al1 faces thereof to the sharpening cutter, then positioning the bit for contact with a gaging miller and rotating the bit in cutting proximity to said gaging-cutter all in one prompt, continuous operation.

The mechanism herein illustrated and described in detail for performing the present improved method, is well suited for this purpose, but is by no means the only machine capable of performing the method. This method could be performed in numerous other ways with the aid of different mechanisms.

While this specification discloses preferred means for reducing the present invention to practice and a preferred embodiment of the invention, changes may occur to those skilled in the art and may be made within the scope of the appended claims, without departing from this inventive concept.

What We claim and desire to secure by Letters Patent is:

l. A device of the character disclosed comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted adjacent said sharpening and gaging means and angularly movable toward and away from each, a bit-driving head automatically engageable with a bit on the holder by angular movement of said holder toward said gaging means, and mechanism for rotating said driving head for gaging the bit.

2. A device of the character disclosed comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted adjacent said sharpening and gaging means and angularly movable toward and away from each, indexing mechanism positioned to contact and to rotate the holder when said holder is angularly moved, a rotary bit-driving head automatically engageable with a bit on the holder by angular movement of said holder toward said gaging means, and mechanism for rotating said driving head for gaging the bit.

3. A device of the character disclosed comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted adjacent said sharpening and gaging means and angularly movable toward and away from each, means inclusive of a rotatable eccentric at the pivotal mounting for said holder and a link`connecting said eccentric with said holder for extending the effective radial length of the holder, a bit-driving head automatically engageable with a bit on the holder by angular movement of said holder toward said gaging means, and mechanism for rotating said driving head for gaging the bit.

4. A device of the character disclosed comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted intermediate said sharpening means and said gaging means and angularly movable toward and away from each, means for circulating a fluid coolant in heat-exchange proximity to the holder, a rotary bitdriving head automatically engageable With a bit on the holder by movement of said holder toward said gaging means, and mechanism for rotating said driving head for gaging the bit.

5. A machine for reconditioning detachable rock drill bits or the like comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted intermediate said sharpening means and said gaging means and angularly movable toward and away from each, a rotary bit-driving head coaxially mounted for selective conjoint angular movement with said holder and radially slidable theretoward, mechanism inclusive of a stationary cam adjacent said axis of angular movement and a cam follower engaging said bit-driving head for automatically engaging said driving head with a bit on the holder when said holder is angularly moved toward said gaging means, and mechanism for rotating said driving head for gaging a bit engaged thereby on the holder.

6. A machine for reconditioning detachable rock drill bits or the like comprising means for sharpening a bit, means for gaging a bit spaced away from said sharpening means, a bit holder pivotally mounted intermediate said sharpening means and said gaging means and angularly movable toward and away from each, a rotary bitdriving head coaxially mounted for selective conjoint angular movement with said holder and radially slidable and spring-urged theretoward, mechanism inclusive of a stationary cam adjacent said axis of angular movement and a cam follower engaging said bit-driving head for automatically engaging said driving head with a bit on the holder when said holder is angularly moved toward said gaging means, mechanism for rotating said driving head for gaging a bit engaged thereby on the holder, and means for extending the effective radial length of said bit holder in predetermined increments.

WILLIAM J. MOERLIN. ROBERT C. BERGGREN. 

